Combustion chamber



April 7, 1931- H s. HEWITT ET AL 1,800,070

COMBTNAT I ON CHAMBER Filed March 7, 1929 Patented Apr. 7, 1931 i UNITED STATES PATENT OFFICE HERBERT STAYTOH HEWITT, OF SURBITON, AND WILFRED AMBROSE WHATMOUGH, OF NEW BARNET, ENGLAND COMBUSTION CHAMBER Application filed March 7, 1929, Serial No. 345,153, and in Great Britain December 11, 1928.

r This invention relates to the combustion chambers of internal combustion engines in which at least one valve in arranged in a cavity at the side of the engine. of the invention is to provide improved filling and exhausting of the cylinder.

According to this invention a combustion chamber for an internal combustion engine comprises in combination a barrel, a lateral 1 cavity in communication with said barrel, a

' valve seating in the inner wall of said cav- -ity, the outer wall of which cavity is so shaped that its contour in the direction of the flow of gases is concavely curved from that edge of the valve seating which is remote from said barrel to at least a location above the center of the valve seating, and a which inner wall as it extends towards the barrel slopes inwardly and meets the barrel at an obtuse angle. The words inner wall denote that wall which istransverse to the axis of the cylinder andnearer the crank shaft of the engine.

When the cavity contains only the exhaust valve, the passage preferably also widens towards the cylinder barrel. 1 The accompanying drawings are purely -diagrammatic, and in these i Figure l is a central vertical section of partof a cylinder of an internal combustion engine taken through the centre of an inlet valve locatedin a 1ateral.eavity,

. Figure 2 is a similar view taken through a the centre of an exhaust valve, and c Figure 3 is a horizontal view showing the shape of the cavity and the passage connecting it with the cylinder barrel when only an exhaust valve is located in the cavity.

Like numerals indicate like parts throughout the drawings.

a The cylinder 2 is formed with a lateral cavity 3 in whieh an inlet valve 4 and an exhaust valve are arranged side by side. Theseatings .6 and 7. forthe valves are, as usual, spaced from the cylinder barrel 2 by a part 8 of the casting which varies in width according to circumstances, generally.

varying with the width of the water space not shown) around the barrel at that point. This entails a passage 9 between the cavity The object and the barrel, and in the present invention the bottom 10 of this passage curves down wards from a point close to the periphery of the valve seatings towards the cylinder barrel. For example, this surface may form part of a circular cylinder whose axis 11 lies beneath the valve seatings. The curve 11 may terminate in a rounded edge 12 running gently into the straight wall of the cylinder barrel or not, as desired, .and it is not essential that the curved surface 10 should form part of a circular cylinder.

Preferably the actual contour is chosen in relation to the roof 13 of the passage so as to provide a gradually deepening passage between the cavity 3 and the cylinder barrel 2 in which there is a minimum of disturbance to flow from the cavity to the barrel during the inlet stroke, and from the barrel to the cavity on the exhaust stroke. During the inlet stroke, whilst the inlet valve 4 is at or near its maximum height, the inlet charge impinges on the underside of the valve, the head of which acts a deflecting bafile tending, to a great extent, to affect the flow along the passage. Prefand is referably shaped to conform to the path 0 these gases, being domed at 50 for this purpose.

0 Whenapplying the present invention to a cylinder eniployin such valves,the shape of the bottom10 of the passage between the cavity and the barrel is formed to agree withthe lines of flow of the inlet charge and exhaust gases, and the roof .13 is shaped to conform to the flow lines over the head of the exhaust valve. The paths of the gases are indicated by the flow. lines and arrows inFigures land 2. It is therefore desirable, when determining the contour of the bottom and roof of the passage, to take into consideration the shapes of the neck of the inlet valve and thehead of the'exhaust valve. 0 1

erably' this is taken into consideration and V Tests have proved that, if the passage is either restricted or incorrectly directed, the exhaust valve is heated by eddying flame. The consequence is that the rate of flame travel is increased, i. e., the angle of spark advance :for agiven-engine speed is zlOWGIQCl. In fact-it is possible by such bad designto make a fuel of'a good anti-knock value into i one which is inherently bad from a detonation point of view.

p Also it has been found possible, by arranging the contour of the bottom ofithe passage in relation to the shape of the inlet valve ,head, to enhance considerably the filling of the cylinder by minimizing the resistance to'fiow, thus higher volumetric efii-V ciency is obtainable.

With a'relatively narrow cavity containing the exhaust valve alone, thewpassage :9

is widened towards the cylinder barrel, as

Well as deepened slightly, as shown in Figures 2 land 3.;

Whatvwe claim as our invention and desire to secure by Letters Patent f the United States is 1. A combustion chamber for an I combustion engine comprising in combination a barrel, at-lateral cavity in communicac tion with saidlbarrel, a valve seating in the inner wall ofsaid cavity, the outer wallof -wliich cavity is so shaped that its contour in the direction of the flow of gases .111 concavely curved from that "edge of the valve seating remote from the barrel to at least a location above the center of the valveseating and whicliinneiwall as it extends towards the barrel is sloped inwardly towards the crank shaft etOimQGtthB barrel at an obtuse angle, which cavity varies gradfinally: in cross section barrel.

:as it approaches the 2. Acombustion chamber for an internal combustion engine comprising in combination'a barrel, .a lateral cavity in communication with said barrel, a valvese'ating'in the inner wall of said-cavity, 'the outer wall of which cavity is so shaped Lthatits contour in the direction of the How of gases is .so

xconcavely curved from that edge of the valveseating which is remote from-thebarrel and over and above thesaid seating that it conforms with theshape of the" head of a valve associated "with said seating and which inner wall as it extends .towards'the barrel is so con-vexl'y curved as-to conform to the flow lines of thegases between the barreland said lateral cavity and each cavity '.=var iesgradually in cross sectionas ap- :proaches thebarrel.

3. A combustion chamber for an internal combustion engine comprising in combination 1 a barrel, a :lateral cavity in communica- 121011 with said barrel, a'valve seating in the inner vwall of said cavity, the outer wall of which cavity is so shaped that its contour internal in the direction of the flow of gases is concavely curved from that edge of the valve seating remote from the barrel to at least a location above the center of the valve seating, and which inner wall as it extends towards the barrel is so-sloped zinwardly f-that itmeets-the barrel "at-an obtuse angle and provides a passageconnecting said cavvalve seating and which :inner wall :as it extends'towards thebarrel is so" inwardly :andconvexly curvedtowardsthe crank shaft of the engine that it provides a passage connecting said :cavity with said barrel which deepens :towards the barrel; w

A combustion chamber for an "internal combustion engine comprising ilIl combination a barrel, a lateral cavity,aipassage connecting'sa'id'cavity with said'tbarrel, an ex- -liaust valve seating in the inner avail of said cavity the outer wall'o'f which cavity is so shaped that its contour in the direction of the flow :of gases is concavely curved from L V I s 0 g n tliaoedge OI :the valve seating which' is reinote from the barrel to at ileast a location above "the center of the valve seating, the i'width "and depth of which-cavity and passage as they extcnd towards the barrel increase and which inner wa'l'l as it extends towards the barrel slopes-inwardly :and

meets the barrel at an obtuse angle.

'6. A combustion" chamber :for an internal combustion engine comprising in combina- "tion .a barrel, a lateral cavity in communication with said barrel, a valve seating in 2 the 'iiiner-zwal'l of said cavity, the outer wall of which cavity is so shaped that its contour in the direction of the how of gases is concavelycurved from that edge "of'the valve seating'to at least a location-above the center of the valve seating," and Y which i inner and outer walls vas they "extend towards the barrel are-so sloped'inwardly 'that'the distance between them graduallyincreasesttrom the cavity to the barreL' .7 ."A combustion chamber for an internal combustion engine comprising in combination a barrel, aila'teral' cavity in; communication with said barrel, -a valve seating in -the inner wall of s'aidmavity,the-outer wall of which cavity is so shaped that its c'ontour in thedirection o'f the flow of gases is con- "cavely curvedfrom tha't edge fof the "valve -.seating;remote from the barrel to at least a "location-above the centre of the valve seating and from thence in a smooth concave curved surface over the barrel and which inner wall as it extends towards the barrel slopes inwardly and meets the barrel at an obtuse angle.

8. A combustion chamber for an internal combustion engine comprising in combination a barrel, a lateral cavity in communication with said barrel, a valve seating in the inner wall of said cavity, the outer wall of which cavity is so shaped that its contour in the direction of the flow of gases is concavely curved from that edge of the valve seating remote from the barrel to at least a location above the centre of the valve seating and from thence extending in an unbroken smooth concave curve over the barrel and terminates in proximity to that edge thereof remote from the valve, and which inner wall as it extends toward the barrel slopes inwardly and terminates at the cylinder barrel with a rounded edge.

9. A combustion chamber for an internal combustion engine comprising in combination a barrel, a lateral cavity in communication with said barrel, a valve seating in the inner wall of said cavity, the outer wall of which cavity is so shaped that its contour in the direction of the flow of gases is concavely curved from that edge of the valve seating remote from the barrel to at least a location above the centre of the valve seating and from thence extends in a smooth concave curve over the barrel and terminates in proximity to that edge thereof remote from the valve in a convex curve, and which inner wall as it extends towards the barrel is so sloped inwardly that it meets the barrel at an obtuse angle and provides a passage connecting said cavity with said barrel which deepens towards the barrel.

10. A combustion chamber for an internal combustion engine comprising in combination a barrel, a lateral cavity in communication with said barrel, a valve seating in the inner wall of said cavity, the outer wall of which cavity is so shaped that its contour in the direction of the flow of gases is concavely curved from that edge of the valve seating remote from the barrel to reach its greatest height at a point immediately above the centre of the valve seating,

and which inner wall as it extends towards the barrel is so sloped inwardly that it meets the barrel at an obtuse angle and provides a passage connecting said cavity with said barrel which deepens towards the barrel.

11. A combustion chamber for an interna l combustion engine comprising in comis concavely curved from that edge of the valve seating remote from the barrel to at least a location above the centre of the valve seating and from thence in a smooth concave curved surface over the barrel and terminating in proximity to the edge thereof remote from the valve and which inner wall as it extends towards the barrel slopes inwardly and meets the barrel at an obtuse angle.

12. A combustion chamber for an internal combustion engine comprising in combination a lateral cavity in communication with said barrel, a valve seating in the inner wall of said cavity, a poppet valve associated with said seating, the outer wall of which cavity is so shaped that its contour in'the direction of the flow of gases is concavely curved from that edge of the valve seating remote from the barrel to at least a location above the centre of the valve seat ing, and that the distance between said outer wall and the valve head measured in any direction with the valve at full lift is substantially constant, and which inner wall as it extends towards the barrel is convexly curved about an axis which is disposed transversely to the axis of the cylinder and externally of the inner periphery of the barrel, and the distance between the inner wall and the underside of the head is substantially equal to the distance between the valve head and said outer Wall.

In testimony whereof we have signed our 

